Hydraulic transmission



Dec. 1, 1942. c, H. EDEN ETAL HYDRAULIC TRANSMISSON 3 Sheets-Sheet 1 FL1ed May 11 1940 lizvenions'. (barles floward Eden. Md .Eiflwenson.

' Dec. 1,' l942. C. H.E'DEVN ETAL 2,303,

HYDRAULIC TRANSMISSON Filed May 11, 1940 3 Sheets-Sheet 2 Dec. 1; 1942-c. H. EDEN ETAL 2,303,635

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Zdwar .J'l'even WW r in and plunger type, and certain features of thePatented Dec. 1, 1942 T-ES PATENT OFFICE 2,303,685 HYDRAULICTRANSMISSION.

,Charles Howard Eden and Edward Los Angeles, Calif.

E. Stevenson,

Application May 11,1940, Serial Nb. 334,558

18 Claims.

This invention relates generally to hydraulic,

vision of a hydraulic transmission, useful as either a motor or a pump,having features of improvement in general design, structure andarrangement, as well as of operation and control.

A further object is the provision of a hydraulic transmission havingimproved means for inversely varying speed and torque by varying thetotal volumetric capacity characterized 'by enhanced facility andflexibility of control.

A still further object is-theprovision of an improved multiple unithydraulic transmission of the cam and plunger type, particularly onehaving means for inversely varying speed and torque through selection ofthe numberof units employed. a

The invention is herein illustrated as embodied the form of a hydraulicmotor of the cam invention deal specifically with that particular typeof motor. In broader aspects, however, such as that in which multiplepower units are employed, with the coupling selected necessarily solimited, and the specifically described cam and plunger units are to beconsidered as merely illustrative of the invention in one of itspreferred forms.

A feature of the invention, in effecting variation of volumetriccapacity and torque, is the provisionof hydraulically controlled meansfor coupling each'power unit of a bank of such units to the next, or tothe power output or input element, whereby either one ,or more oftheunits may beput into operation. A further and preferred featureof theinvention is the provision of means whereby the application of pressurefluid to successive power units. automatically results in successivelycoupling said units to the power output or input element,

Certainlfeatures of the invention deal with novel and unique means forselectivelyintercoupling and driving the units of a bank of alined rotorunits of the cam and plunger type.

provision of means for inter-.

units, the invention is not Thepressure fluid may be delivered wholly tothe. first of the rotor units, with the remainder of said unitsuncoupled therefrom, in which event maximum speed and minimum torqueobtain, or selected numbers of the units may be intercoupled and thepressure-fluid divided among those units, with the result of decreasedspeed but increased torque. L

Various additional objects and features of the invention will appear andbe made apparent in the course of the following detailed description ofa present preferred illustrative embodiment, reference being directed tothe accompanying drawings, in which:

Fig. 1 is a view partly in side partly in longitudinal medial section,showing an embodiment of the invention;

Fig. 2 is a diagrammatic perspective, showing the end portion of thedistributer shaft of the unit of Fig. 1, and showing, in diagram, avalvular and circulation syste Fig. 3 is a transverse section taken online 3-3 of Fig. 1;

Fig. 4 is a transverse section taken unlined-4 of Fig. 1;

Fig. 5 is a transverse section taken on line 55ofFig.1; V

Fig. 6 is a transverse section on line 6-6 of Fig. 1;

Fig. 7 is a transverse section taken on line 1'| of Fig. 1;

Figs. 8 and 9 are transverse sections similar to Figs. 6'and 7, butthrough corresponding portions of the rotor unit next adjacent to thatof Figs. 6 and 7 Fig. 10 is a transverse section taken on line Ill-I0 ofFig. l; and

Fig. 11 is a sectional view of avalve unit which may be substituted forcertain pairs of valves shown in Fig. 2. a 1

The invention will be hereinafter described as A a multiple-rotorhydraulic motor, though it will be understood that by simply applyingpower to.

.the power shaft of the motor, it may be transtherefore be prefaced by apreliminary discussion of the functions of a diagrammaticallyillustrated circulation and valve system adapted for use in connectionwith the motor. It will be understood that a valvular control mechanismand elevation and circulation system to perform these functions may bemechanically designed in a variety of manners. Reference accordinglybeing directed first to Fig. 2, 'we indicate at l2 a fluid circulatingpump, which may beeither a variable or constant volume pump, and whichwill be understood to be driven by any suitable prime mover sucha's-an'electricmotor, not illustrated.v The ..output from pump I2 isdelivered via conduit I3 posed axially of the motor generally indicatedat 23, the passageways I1 and I8 communicating with one rotor unit ofthe motor as later to be described. In the present instance the member19 is in the form of a stationary central'distributer shaft, ported 'todirect fluid to one or more units; The passageways I1 and [8 are hereshown as disposed .on opposite sides of the longitudinal axis of shaftl9. Branch conduit |5 has two branches I50, and Ho, which connect withlongitudinal passageways 2| and 22 in shaft l9, positioned just outsidethe aforementioned passageways I1 and I8, and which will be'understoodas communicating with a second rotor unit of the motor. Similarly,conduit l6 has branches lGa and "5b connected to longitudinalpassageways 23 and 24 in shaft Id, disposed just outside passageways 2|and 22 and which will be understood as communicating with the thirdrotor unit of the motor.

Fluid exhausted from the several rotor, units returns to pump l2 by wayof a conduit 25, lead- Ting from branch conduits25, 21- and 28, of whichconduit 26 connects. with branch conduits 26a and 26b leading fromlongitudinal fluid discharge passageways and 3| formed in shaft I9 insymmetrical relation but'spaced'90 from the previously describedpassageways I1 and |8,'the passageways 3lland 3| receiving fluidexhausted from the first rotor unit. Similarly,

leads from branches 21a and 2"; connected to longitudinal fluiddischarge passageways 32 and branch conduit 21 33 formed in shaft I9just outside passageways 30 and 3|, respectively, and being understoodas 40, 38 and 4|, and 39 and 42, may each be simultaneously actuated ifdesired.

It will be evident that with valves 31 and 40 open and with theremaining valves closed, the output from pump |2 will be deliveredtotally to longitudinal passageways l1 and H3 in distributer shaft l9,and it will later become apparent that this total volume of fluid'isused to drive the first rotor of the motor, and is then returned to thepump'via passageways and 3|. With valves "38 and 4| also open,'theoutput from the pump will be'divided' between passageways 30, 3|, Hand33, of which the two latter lead to the second rotor of the motor, andwill be returned via passageways l1, I8, 2| and 22. And with all valvesopen, the output divided between passageways ll, 3, 2|, 22, 23 and 24,to be divided between the three rotors of the motor, and will bereturned via passageways 30, 3|, 32, 33, 34 and 35.

Motor 20 embodies a plurality of coaxial, alined rotor units, of whichthere may be any desired number, though we have here illustrated threesuch units A, B and C. These rotor units surround distributer shaft l9,in end to end opposition with one another, Each such unit,,such as -A,-comprises a cylinder and plunger assembly embodying a centrally boredcircular cylinder member 50 having a rotating and fluid sealin fit onshaft l9. In the particular illustrative embodiment of the inventionhere being described, cylinder member 50 is a rotor, although merereversal would make it a stationary part. In any case it and shaft l9are relatively rotatable and it will be understood that in using theterm rotor we mean to imply only relative rotation. Preferably shaft'l9does not serve as a bearing for the rotor, so that the fluid sealing fitwill not be subject to any substantialwear.

receivingexhau'st fluid from the second rotor unit, while branch conduit28 leads from branches 28a and 28b connected with longitudinal fluiddischarge pass'ageways 34 and 35 formed in shaft lQandpositiqned justoutside passageways 32 and 33, respectively, and being understood asreceiving exhaust fluid from the third rotor unit There is thus provideda'closed circulation systern, the circulated medium, which may be oil,air, inert gas, steam, etc., being delivered continuously. from to thepump. I

Distributer .Valves 31, 38 and 39 are indicated as placed in conduitsand distributer valves sto beunderstood that the showing of the uitsystem. and valves of'Fig, 2 is entirely the type of closed circuitdistributive b be' jemployed; and that the system and 42,,mayinpra'cticebe any suitable typeof unitaryvalve and fconduit structurecapable of performing the functions 'to'be described. It will laterbeexplained how the pairs of valves 31 and Bearing arrangementsarerather provided between the member l9 and cylinder member 50. Cylindermember has two axially spaced sets of radially disposed cylinder bores5| and 52, in which are mounted lap-,fitted hardened plungers 53 and 54.It may here be mentioned that the cylinder bores and plungers forsuccessive units A; B, etc., may all be of the same diameter, though ashere shown the diameter is reduced in the instance of unit B. The reasonfor this will be set forth at a later point in the specification.

The outer ends of the two sets of plungers53 and 54 of each rotor engagethe hardened elliptical cam faces 55 and 56 of a pair of stationary camrings 5! and 58, respectively, the latter seatingon annular seats 59aformed at opposite edges of a seating ring 59 mounted within theexterior motor housing generally designated at 60.

the pump, circulated 'to and from I selected rotors of the motor, andthen returned 60,

|4, l5 and I6, respectively, 40, 4| and 42 are indicated placed inconduits 26, .21 and 28, respectively.

As here :shown, housing 60 is made-up of a pair of end members SI and62, provided with integral supports 6|a and 32a, respectively, and oneor more intermediate members 53, which are assembled about theseveralrotor units A, B; etc., as shown, and are provided with abuttingflanges secured together by screws 64. The adjacent housing members haveopposed faces 65 which' engage and tightly clamp the cam andseatingrings between them when the screws 64 are set up, all as will be clearlyunderstood from an inspectionof the drawings. It will be understood thatwith this construction, thetransmission may be made up with as manyrotor units as desired, it only requiring that a distributer shaft l9 beselected of a length and with fluid passagewaysproper for thenumber ofrotor units selected.

from the pump will be i9 in the radial End casting 62 of housing 60 isprovided with a reduced hub 70 and distributer shaft I9 is keyed to thishub as indicated at H. End casting 6! of'housing 60 is provided with areduced hub 12, within which is journaled a power shaft H, the latterbeing mounted in coaxial relation with stationary distributer shaft i9.Formedv on the inner end of shaft M is an enlarged cup-like extension15, which reaches over the end of shaft 19 and engages and is drivinglyconnected with the cylinder member 50 of first rotor unit A. As

a typical means for .providing driving connection between cylindermember 58 and member 15, we

here simply show dowel pins 16. Cup member is supported by a bearing 11seated within end housing member BI, and shaft M is supported by abearing 18 located immediately in back of or adjacent cup member 75,said bearing 18 being -seated withinhub 12, as illustrated, and beingspaced from hearing Tl as by spacer sleeve19. A collar .80 is shown asscrewthreaded on shaft 14 and set up against the inner ring 1841. ofbearing 18.

The inner end of stationary distributer shaft is. is received withrotational fit within the cup member 15 on the end of rotatable shaft74, the end portion of shaft 59 having a reduced extremity 82, which issupported within a bearing 83 seatedinside cup member 15 between annularshoulder 84 on shaft I9 and an end disk '85s held by a screw 85 threadedinto the end of shaft extremity 82. The cup' member 75 on theinner endof shaft It is thus supported for rotation;

on the inner end of stationary shaft I 9.

Stationary shaft is and rotatable shaft it are provided with-suitablefluid packing inside the respective housing hubs ill and 12, asindicated at 88 and 89, respectively.

The previously mentioned longitudinal pressure fluid passageways i! andi8 in distributer shaft is communicate with pressure fluid ports 90 and9|, which open through opposite sides of shaft plane of the=first set ofplungers 53. Longitudinal exhaust fluid passageways 3d and SI in shafti9 communicate in like manner with'exhaust fluid ports 92 and 93 ofsimilar type opening through opposite sides of shaft is and locatedsymmetrically or at equal spacing with reference to ports 96 and 9!, allas clearly. illustrated in Fig. 3. Ports 9!), Hi, 92 and 93 communicatewith the inner ends of successive cylinder bores 5! during rot ber 5B,as will be obvious.

Assuming the parts to be in the position of Fig. 3, it will be evidentthat the fluid under pressure within ports 98 and M will act against theinner ends of the associated plungers 53 to move said plungersoutwardly, forcing their outer ends against the inclined plane presentedby the elliptical face 55 of cam ring 51, and thereby causing thecylinder member 50 to rotate in a counter-clockwise direction as viewedin Fig. 3. The portion of the elliptical cam face opposite the plungerswhose inner ends are in communication with ports 92 and 93 forces saidplungers radially inwardly, said plungers thus forcing exhaust fluidthrough ports 92 and 93 into-exhaust passageways 30 and 3!. Eachplungercylinder is in communication with each of the two pressure and twoexhaust ports for about 90 of rotation. Of course, by utilizingpassageways 30 and 3| for pressure fluid and passageways I1 and 18 forexhaust fluid, the direction of rotation may be reversed. Reference isnow directed to Fig. 4, showing ation of cylinder mem- A, the exhaustfluid bein plungers 54 and the second elliptically faced cam ring 58 ofrotorunit A. Pressure fluid passageways i! and H3 in shaft l9communicate with ports and 9!, opening through opposite sides of shaft19 in the radial plane of the second set of plungers 54, and dischargepassageways 3D and 35in shaft l9 communicate with ports 92' and 93'opening through opposite sides of said shaft in the same plane, thearrangement being the same as that of the section of Fig. 3, exceptingthat the several ports 90', 9|, 92' and 93.. are displaced by 90- ascompared with the corresponding ports 90, 91, 92 and 83 of Fig. 3. Alsoas will be evident from the second set of a comparison of Figs. 3 and 4,the major'axis of 1 the elliptical cam face 56 is likewise displaced by90 as compared with the major axis of the elliptical cam face 55. Thesecond set of arms as the set of plungers 53, being displaced by 90 fromthe first set, the flow of power delivered to the rotor by both sets issubstantially equally distributed throughout the full 360 of rotationReference now being directed to Figs. 1, 6 and 7, it will be understoodthat rotor-unit B is-the same in all substantial respects as rotor unitA,

differing only in the diameter of the plungers,

which is subject to modification, and the same is true of rotor unitC,shown partially in section in Figs. 8 and 9. Corresponding elements ofthe 1 'ro'tor units A, B a d C are for convenience designated by similarreference numerals, but with the sub letter b adjoined in the case ofunit B and with the sub letter 0 adjoined in the case, of unit C.Reference to Figs. 6 and 7 will show that I the pressure fluid ports 9%and Qib which deliver pressure fluid to plungers 53b fluid fromlongitudinal distributor passageways 2i and 22, respectively, and thatpressure fluid ports-90b and Nb which deliver to plungers 54b likewisereceive pressure fluid from passageways 2i and 22, respectively. Theexhaust fluid .ports Nb and @317, corresponding to plungers 531),communicate with exhaust passageways 32 and 33, respectively, andsimilarly the exhaust ports 92b and 93b corresponding to plungers 5thcommunicate with exhaust fluid passageways 32 and 33, respectively. It,will be understood that when pressure fluid is delivered via passageways2i and 22, rotor unit B will be driven in the manner previouslydescribed in connection with rotor unit g returned via passageways 32and 33. V

Figs. 8 and 9 show that the pressure fluid and exhaust ports whichdeliver pressure fluid to and receive exhaust fluid from rotor unit Ccommunicate in a similar manner with the pressure fluid passageways 23and 24, and exhaust fluid passageways 34 and 35, respectively, ofdistributer shaft 89. As additional rotor units are incorporated in themotor, the distributer shaft will have additional pressure fluidpassageways located outside the passageways illustrated, and thepressure fluid and exhaust fluid ports will communicate ,therewith'in amanner similar to that shown in the units illustrated. Thus, while wehave here shown but three rotor units, it will readily be understood howeither more or less of such rotor units may be employed, and the presentillustration of three rotor units will be understood as implyi nolimitation on the number of such units that may be employed in practice.

From the foregoing description it will now be understood that rotorAwill be propelled, and

receive pressure will propel power take-off shaft 14, if pressure fluidbe supplied to distributer passageways and I8; rotor B will also bepropelled if pressure fluid be supplied to distributer passageways 2|and 22, and rotor unit C will also be propelled if pressure fluid besupplied to distributer passageways 23 and 24., And it has beendescribed how the flrst rotor A of the bank of 'rotors is per-' manentlycoupled to power shaft M. There re-, mains for description means inaccordance with the invention for coupling the successive remainingrotor units B, C, etc., to the power shaft as pressure fluid isdelivered to them. A feature of the invention is the provision of clutchmeans j for coupling up the successive rotor units B, C, etc.Specifically and preferably this is shown as clutch mechanism forsuccessively coupling the several units to the one just ahead of it inthe series. A further feature is the provision of means whereby thecoupling of successive rotor units is accomplished hydraulically andautomatically by virtue of an application of the pressure fluid tosuccessive clutch units as it is delivered' to successive rotor units.One form of illustrative means for accomplishing the purposes statedwill now be described. 7

The cylinder members 56 of the several rotors are formed on their sidesremote from power take-off shaft 14 with axial annular projections .95surrounding shaft'l9, and these projections 95 are over-lapped by andreceived within axial, annular projections 96 extending from the opposedsides of adjacent cylinder members 56, the meeting surfaces of theprojections 95 and96 being formed with running fit. An annular recess 91sunk in the periphery of projection 96 and the annular face 98 of theadjacentcylinder member 56cooperate to provide a seat for the inner ringof a ball bearing assembly 99, the outer ring of which is seated againsthousing member 63.

Hydraulically actuated clutch means presently to be described actbetween the overlapping annular' projections 95 and 96. The lastcylinder member 56 of the series is provided with an annular, axialprojection H16, unequipped with clutch means, andsupported-bya bearingseated within end housing member 62. l

The clutch means inthe illustrative form here shown embodies a pluralityof plungers H0 disposed radially of annular projections 95 and 96 (seeFigs. 1 and with enlarged piston heads HI on their inner ends. .Heads H|reciprocate in radial cylinder bores H2 formed in annular projection 95and opening to distributer shaft 19, the plu'ngers'HD working inreducedradially disposed bores H3 extending from bores H2 through projection95, the bores H3 being adapted to register with similar radiallydisposed bores Min overlapping projection 96, into which the plungersare adapted to be projected. 'The outer ends of bores H4 may be providedwith plugs |5=to prevent the escape of any pressure fluid leaking pastplungers H0. The, cylinder space outside each piston head I is incommunication via a fluid passageway H6 (Fig. 1) with an annularperipheral groove H'l extending around distributor shaft l9, whichgroove reunit B via fluid passageways 2| and 22, part of The cylinderspace inside each clutch piston head III for rotor unit B is incommunication with pressure fluid passageways 2| and 22 of the adjacentrotor unit B via angularly disposed fluid passageways I20 and aperipheral groove |2| extending around shaft l9 at a point oppositecylinder bores H2. Corresponding arrangements will be understood to bemade for the cylinder spaces below the clutch piston heads for rotorunit C.

Assuming that only unit A is in operation, which condition is broughtabout by opening control valves 31 and 46, valves 38, 39, II and 42being closed, the entire volume of fluid delivered by pump I2 is.supplied to the rotor of unit A, and pressure fluid accordingly flowstothe cylinder spaces above clutch piston heads I of unit- B. At such timethere will be no pressure fluid within the inlet passageways 2| and 22for rotor unit B, and there will hence be no pressure fluid actingoutwardly on said clutch piston heads IH of unit B. The piston headswill accordingly be held in an inwardly retracted position, with theplungers I ll] removed from the bores! M in member 96, so that rotorunit A is' free to revolve independently of rotor unit 3 which merelyfloats.

' Assuming next that rotor unit B is to be cut in, valves 38 and 4| areopened, with the result that pressure fluid from pump l2 is dividedbetween passageways I1 and I8 leading to rotor Aand passageways 2| and22 leading to rotor B, the total volume of fluid delivered to the motorremaining the same as before. The pressure fluid now flows frompassageways 2| and 22 via passageways I20 and groove |2| to the cylinderspaces below clutch piston heads I'H of rotor B, so that there is thenfluid at the same pressureabove and below said piston heads Now becauseofthe differential of effectiveareas above and below piston heads H I,the plungers will beforced outwardly to the clutching position illus-'trated in Figs.'1 and 10, the plungers finding and engaging in theradially disposed bores H in projection 96 and thereby acting to clutchrotor B 9 to rotor A and thence to power shaft 14.

Fig. l of the drawings shows rotor C de-clutched from rotor B, theclutch plunger members being; in inwardly retracted position caused byapplication of the fluid pressure from passageways 2| and 22' to thespaces outside pistons H|-, there being nopressure fluid inside saidpistons owing to the control valves 39 and 42 being closed.

Thus as the control valves are operated to supply pressure fluid tosuccessive rotors beyond the first (permanently'coupled) rotor of theseries,

ceives pressure fluid byway of a pair of fluid passageways H8 and H9insaid shaft from pressure fluid passageways I1 and I8, respectively;The pressure fluid flowing in passageways I'land l8, and beingdelivered'to drive rotor A, is thus constantly acting outside pistonheads HI, tending to force said heads radially inwardly. Ina likemanner, when pressure fluid is supplied to rotor hydraulically actuatedclutch means automatically operate to couple the successive rotors tothe one next ahead, and thus to the power shaft.

It will be evident from what has been said that with the control valvesin a position to deliver the total output of pressure fluid ofpump-|2 tofluid passageways I1 and I8, rotor A-will be driven" and the remainingrotors will be de-cl'utched and idle, power take-off shaft 14 'beingdriven directly and solely from rotor A. Under such circum stances, thespeed of rotation is at a maximum. If increased torque, with reducedspeed, should be. required. the control valves are maninulated i'n a aredriven, with the result creased speed but correspondingly increased thevalves of each such lines l4 and 26 of divide the pressure fiuid betweenpassageways l1, 18, 2| and 22, which results in clutching rotor Btorotor A, and at the same time dividing the been'increased. Now bymanipulating the comtrol valves to distribute the pressurejfluid be-.

tween all three rotors A, B and C, rotor C is automatically clutched torotor B,

and all three rotors torque. e

- ,Attention is called to the smaller diameter of the plungers of rotorB as compared with the plungers of rotor A. These plungers as well asthe plungers of rotor C, may all be ofthe same diameter, in which casecutting in rotor B would result in reducing the speed byone-half andmultiplying the torque by two, while cuttingv .in rotor would result inreducing the original speed by one-third and multiplying the originaltorque by three. These speed and torque ratios may be modified asdesired by proportioning the relative diameters of. the plungers of theseveral rotors, ingly shown as of a diameter somewhat less than diameterof the plungers of rotor A.

It will be noted that the pairs of control valves 31 and 4c, 38 and M,and 39 and 62, may preferably be opened and closed together. Fig. -11shows merely diagrammatically how the two pair may be operated by asingle manual manipulation.- Thus, the fluid Fig. 2' may be connected tofitted with a valve plug It! having .two ports M2 and i413 whichconstitute the valves 31 and 38, and which are adapted to be registeredsimultaneously with the inlet and outlet connections of the valve bodywith said a valve] body I #0 lines l5 and 25. Valve plug Edi may beoperated by asinglemanual lever or handle M5. It will be understood thatsuch a valve may be substituted for each of the pairs of valves 37 andd9, 38 and 4!, and 39 and 52. Or the several pairs of valves 31, so and38, Hi and 39, 82, may all be constituted in one valve mechanism. Fig.

' .llshows'the pairs 31, as and 38, iii .so constituted in a singlevalve device, the ports M6 and M1 constituting the valves 38 and t! tocontrol the passages to and from rotor unit'B. The several ports torotor A will be simultaneously opened first: and then, while those portsremain open, the ports-controlling the passages for unit B will besimultaneously opened by further valve movement. Thus the control of allthe rotors may be incorporated in a single valve device.

The hydraulic transmission of the present invention' has now beendescribed principally as a motor, though as above noted, by simply aplying power to the power take-oil shaft '14, it may be transformed intoa pump. The claims are therefore to be construed to cover thetransmission whether used as a motor or as a pump. Moreover, certainreversals of stationary and rotating members are possible, and are to beconsidered as the full equivalent of the specific embodimentillustrated, and as coming within the scope of the claims appendedhereto. Thus, while in the particular embodiment of the invention hereillustrated, the distributor shaft l9 and the cam rings are stationary,with the cylinder members 50 rotatable, these and the plungers of rotorB are accord' are so shaped that the passages.

of still further debe reversed, and the claims are to be construedverition or of the appended claims. r

We claim:

1'. In a .fluid pressure mechanism, the combination including aplurality of coaxial hydraulic rotors, a rotatable shaft, andhydraulically controlled means for coupling selected rotors to saidshaft by virtue of application of pressure fluid to the respectiverotors. I 2. In a fluid pressure mechanism, the combination including aplurality oi coaxial rotors, separate fluid passageways adapted toconvey pressure fluid to and from selected rotors, a rotatable shaft,and means controlled by the pressure of the fluid in passagewaysassociated with theselected rotors for coupling 'said selected rotors tosaid shaft.

3. In a fluid pressure bination including hydraulic rotors, clutch meansfor mechanism, the coma plurality of alined coaxial and hydraulicallycontrolled coupling to one of said rotors any selected number of theremaining rotors by virtue of application of pressure fluid to theselected rotors.

4. In a fluid pressure mechanism,,the combination including a series ofalined coaxial rotors, separate fluid passageways adapted to conveypressure fluid to and from selected rotors,

tween successive and "hydraulically actuated clutch means berotors ofthe series for coupling said rotors successively to the first rotor ofthe series by virtue of the flow offluid in the passageways associatedwith the successive. rotors.

5. In a fluid pressure mechanism, the combination including-a pluralityof alined coaxial rotors, separatepairs of pressure fluid and exhaustfluid passageways for conveying fluid to and from successive rotors,unitary valve means for correspondingly controlling the pressure fluidand exhaust fluid passageways for each rotor, and hydraulically actuatedclutch means or each rotor for clutching that rotor to the next, saidclutch eans being actuated by fluid pressure within the pressure fluidpassageway for that rotor.

' 6. In a fluid pressure mechanism, the combi- 1 the other, andactuatable by the presence of fluid relations may to couple cheer thepressure in the passageway connected with the other rotor to uncouplethe rotors.

7. In a fluid pressure mechanism, the combination including two alinedcoaxial rotors, separate pressure fluid passagewayscommunicating witheach of the rotors, a clutch member adapted 4 rotors to the other, theclutch members of a he inmember comprising a plunger mounted in a rotorand projectible into coupling engagement with another rotor, andincluding opposing differential pressure areas, meanscommunicating-pressure from the fluid passage of said other rotoractuatable rotors associated with the. shaft,

- clutch means selectively actuatable by fluid presto the lesserpressure area of the plunger, and

means communicating pressure from the fluid passage of said one rotor tothe greater pressure."

area of the plunger.

8. In a fluid pressure mechanism, the combisure in the closedcirculatory circuit to 'couple' one at least of .said rotors to theshaft,an d means for controllably varying the speed and torque of theshaft by selectively applying fluid pressure of the closed circuit tothe clutch means nation of a rowof alined axially bored rotors,

each of which comprises a body havinga plurality of radially disposedcylinder bores and a plurality of plungers mounted in said cylinderbores, an elliptical cam ring engaged by the outer portions of saidplungers, a rotatable shaft coaxial and drivingly connected with therotor at one end of said row, pressure fluid and exhaust fluiddistributing means for the cylinder bores of each of said rotorsextending through the-axial bores of said rotors and-opening to theinner ends of the cylinder bores of said rotors, and selective fluidpressure actuated clutch means for clutch ing adjacent rotors to oneanother to couple any,

selected number of said rotors to said end rotor, the clutch means forso coupling a given rotor to said end rotor being actuated by thepressure of the fluid distributed to said rotor by said distributingmeans.

9. In a fluid pressure mechanism, the combiand applying fluid pressureof the closed circuit to the" corresponding rotor.

13. A fluid pressure motor for a fluid pressure system including a pumpin a closed circulatory system with such motor and in which a givenvolume of fluid may be continuously circulated through the motor,characterized by a power delivery shaft and a plurality of fluidpressure a'ctuatable-rotors associated with the'shaft, and

' one of the rotors being rot'atively coupled with -the shaft, thecirculatory system having a branch which applies fluid pressure to saidshaft coupled rotor and another branch capable of applying fluidpressure to another of therotors, clutch means actuatable by fluidpressure inthe second mentioned branch .to couple the second mentionedrotor to the shaft, and valvular means for controlling thesecondmentioned branch.

14. In a fluid pressure mechanism, the combination including a pluralityof rotors adapted nation of a relatively stationary distributer shaft,

a row of relatively rotating rotors rotatably mounted in end to endopposition about said distributer shaft, each of said rotors comprisinga rotatable body having a plurality of radially disposed cylinder boresand a plurality of plungers mounted in said bores, a relativelystationary elliptical cam rin engaged by the outer portions of saidplungers, longitudinal pressure fluid and exhaust fluid passageways insaid distributer shaft for each of said rotors, said passageways openingthrough the sides of said shaft to the inner ends of the cylinder boresof corresponding rotors, fluid pressure actuated clutch means forclutching adjacent rotors to one another to couple any selected numberof said rotors to operate coactively when connected together, andhydraulically controlled clutch means or coupling one of the rotors toanother, actuatable by virtue of application of pressure-fluid to theone rotor to couple that rotor to the other and actuatable by virtue ofapplication ofpressure .fluid to the other rotor to uncquple the rotorsone from the other.

15. In a fluid pressure mechanism, the combination of a row of alinedaxially bored rotors ea'ch provided with a fluid pressure operativeele-' .ment having pressure communication with its axial bore,arotatable shaft coaxial and drivingly connectedwith the rotor at oneend of the row, pressure fluid and exhaust fluid distributing means forthe pressure operati several rotors extending through the axial bores tothe rotor at one end of said row, the clutch Y means for so coupling agiven rotor to said end' rotor being actuated by the pressureof thefluid distributed-to said rotor by the associated fluid pressurepassageway-in said, distributer shaft.-

10. In fluid pressure mechanism, the combi-' nation including a centralrelatively fixed fluid pressure distributing shaft, a plurality of fluidpressure'rotors mounted concentrically about the distributing shaft,said central shaft having sep-.

arate longitudinal passages and lateral ports for the several rotors,and a single valvular device for controlling all said' passages.

11. In fluid pressure mechanism, the combination including a centralrelatively fixed fluid pressure distributing shaft, a' plurality offluid pressure rotors mounted concentrically about the distributingshaft, said central shaft having separate longitudinal passages andlateral ports for the several rotors, fluid pressure actuated clutchmeansior coupling the several rotors together, and a single valvulardevice for controlling all said passages.

12. A fluid pressure motor for a fluid pressure system including a pumpin a closed'circulatory system with such motor and in which a givenvolume of fluid may be continuously circulated through the motor,characterized by a power delivery shaft and a plurality of fluidpressure of the rotors and opening tothe several pressurecommunicationsof the rotors, and selective fluid pressure actuatedclutch means for clutching adjacent rotors to one another to couple anyselected number of said rotors to said end rotor,

row, a. relatively stationary distributor shaft extending longitudinallythrough the-several axial bores' of the rotors, longitudinal pressurefluid and exhaust fluid passageways in said distributor shaft for eachof said rotors, said passageways" opening through the sides o!v saiddistributor shaft to the several pressure communications of the rotors,fluid pressure actuated clutch means for clutching adjacent rotors toone another to couple any selected number of said rotors to the rotor atone end of said row, the clutch means for so coupling a given rotor tosaid end rotor being actuated by the pressure of the .fluid dis,-

tributed to said rotor by the associated fluidpressure passageway insaid distributor shaft.

17. In a fluid pressure mechanism. the come elements of the bination ofa row of alined co-axial fluid-pressure-operative rotors, a rotatableshaft drivingly connected to the rotor at the head end of the row,clutches associated with each of the other rotors and selectivelyoperative by virtue of fluid pressure supply to-the several other rotorsto couple each respective other rotor to the rotor next ahead of it inthe row, and a unitary valve and distribution means operative to applyfluid pressure successively to all the'rotors in their sequence in therow beginning with the rotor at the head end.

18. In a fluid pressure mechanism, the combination of a row of alinedco-axial fluid-pressure-operative rotors, a rotatable shaft drivinglyconnected to the rotorat the head end of the row, clutches associatedwith each of the other rotors and selectively operative by virtue offluid pressure supply to the several'other rotors to couple eachrespective other rotor to the rotor next ahead of it in the row, theclutches being further selectively actuatable by virtue of fiuidpressure supply to the rotor next ahead to uncouple the rotor associatedwith the corresponding clutch, and a unitary valve and distributionmeans operative to apply fluid pressure successively to all the rotorsin their sequence in the row beginning with the rotor at the head end.

- CHARLES HOWARD EDEN.

EDWARD E. STEVENSON.

